Evaluation of Mechanical Properties of Porous Chitosan/Gelatin/Polycaprolactone Bone Scaffold Prepared by Microwave Foaming Method

Shihan Wulin; Bing-Chiuan Shiu; Qian-Yu Yuan; He-Qin Zhangjian; Jia-Horng Lin; Ching-Wen Lou

doi:10.3390/polym14214668

Evaluation of Mechanical Properties of Porous Chitosan/Gelatin/Polycaprolactone Bone Scaffold Prepared by Microwave Foaming Method

Polymers (Basel). 2022 Nov 2;14(21):4668. doi: 10.3390/polym14214668.

Authors

Shihan Wulin¹, Bing-Chiuan Shiu¹, Qian-Yu Yuan², He-Qin Zhangjian³, Jia-Horng Lin^{1

2

3

4

5}, Ching-Wen Lou^{2

4

6

7}

Affiliations

¹ College of Material and Chemical Engineering, Minjiang University, Fuzhou 350108, China.
² Innovation Platform of Intelligent and Energy-Saving Textiles, School of Textile Science and Engineering, Tiangong University, Tianjin 300387, China.
³ Advanced Medical Care and Protection Technology Research Center, Department of Fiber and Composite Materials, Feng Chia University, Taichung 407802, Taiwan.
⁴ Advanced Medical Care and Protection Technology Research Center, College of Textile and Clothing, Qingdao University, Qingdao 266071, China.
⁵ Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 40402, Taiwan.
⁶ Department of Bioinformatics and Medical Engineering, Asia University, Taichung 41354, Taiwan.
⁷ Fujian Key Laboratory of Novel Functional Fibers and Materials, Minjiang University, Fuzhou 350108, China.

Abstract

Bone tissue may suffer from bone injury and bone defects due to accidents or diseases. Since the demand for autologous bone and allograft tissue far exceeds the supply, bone scaffolds have taken the lead. The use of bone scaffolds is one of the measures to help heal or regenerate bone tissue. Therefore, a new bone scaffold was proposed in this study, which has a simpler preparation process and stronger performance. This study proposes bone scaffolds with an attempt to use polymers that are synthesized separately with three types of minerals as the filler using the microwave foaming method as follows. A 0.1 wt% of montmorillonite (MMT), zinc oxide (ZnO), or titanium dioxide (TiO₂) is added to chitosan (CS)/gelatin mixtures, respectively, after which sodium bicarbonate is added as a foaming agent, thereby forming porous gels. The polymer synthesized from three minerals was used as filler. The following microwave foaming method was adopted: 0.1 wt% MMT, ZnO, or TiO₂ was added to the CS/gelatin mixture, and then sodium bicarbonate was added as a foaming agent to form a porous gel. Next, porous gels and polycaprolactone were combined in a self-made mold in order to form bone scaffolds. A stereo microscope is used to observe the morphology of bone scaffolds, after which the pore size analysis, pore connectivity, swell property, porosity, and compressive strength are tested, examining the effects of the mineral type on bone scaffolds. The test results indicate that with MMT being the filler and sodium bicarbonate being the foaming agent, the resulting bone scaffolds yield a porous structure with a pore size between 120 μm and 370 μm. Besides, the incorporation of polycaprolactone also provides samples of 1MCG-P, 2MCG-P, and 5MCG-P with a certain compressive strength of 150-170 MPa. To sum up, the test results substantiate that a combination of the microwave foaming method and MMT generates a porous structure for bone scaffolds (1MCG-P, 2MCG-P, and 5MCG-P), involving a porosity of 38%, an inter-connected porous structure, and the compressive strength that exceeds 150 MPa.

Keywords: bone scaffold; chitosan; gelatin; microwave method; mineral; montmorillonite; titanium dioxide; zinc oxide.

Grants and funding

This research was funded by [Minjiang University President’s Fund] grant number [103952022126].